Vulnerability-Lookup

CVE-2026-81100 (GCVE-0-2026-81100)

Vulnerability from cvelistv5 – Published: 2026-08-27 14:50 – Updated: 2026-08-29 11:48

Title

Timescale tiger-gh-mcp-server DNS Rebinding via Disabled Host Header Allow-List

Summary

tiger-gh-mcp-server started its MCP HTTP transport without enabling the host allow-list the underlying SDK provides. src/httpServer.ts called the shared httpServerFactory helper and never set the DNS-rebinding-protection option, so the transport accepted a request whatever host it named, making the locally reachable GitHub MCP endpoint drivable from a page in a visitor's browser that pointed a name it controlled at the bound address. The fix passes the option explicitly alongside a dependency update; the update alone would not have closed it. The repository has published no release that brackets the fix, so the affected boundary is the commit preceding it.

Severity

7.6 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

6.8 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-29 03:01 UTC

CWE

CWE-346 - Origin Validation Error

Assigner

VulnCheck mitre root

References

3 references

URL	Tags
https://github.com/timescale/tiger-gh-mcp-server	product
https://github.com/timescale/tiger-gh-mcp-server/…	issue-trackingpatch
https://www.vulncheck.com/advisories/timescale-ti…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version	CPE status
timescale	tiger-gh-mcp-server	Unaffected: e559b57b57cf61277525ec96bbf1edcf01b16a21 (git) Affected: 0 , < e559b57b57cf61277525ec96bbf1edcf01b16a21 (git)	guessed

Date Public

2026-08-26 00:00

Credits

Avishai Gonen (Pluto Security)

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-81100

Vulnerability from fkie_nvd - Published: 2026-08-27 17:20 - Updated: 2026-08-29 04:18

Severity

6.8 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Summary

References

	URL	Tags
	disclosure@vulncheck.com	https://github.com/timescale/tiger-gh-mcp-server
	disclosure@vulncheck.com	https://github.com/timescale/tiger-gh-mcp-server/pull/36
	disclosure@vulncheck.com	https://www.vulncheck.com/advisories/timescale-tiger-gh-mcp-server-dns-rebinding-via-disabled-host-header-allow-list

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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  "references": [
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/timescale/tiger-gh-mcp-server"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/timescale/tiger-gh-mcp-server/pull/36"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://www.vulncheck.com/advisories/timescale-tiger-gh-mcp-server-dns-rebinding-via-disabled-host-header-allow-list"
    }
  ],
  "sourceIdentifier": "disclosure@vulncheck.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-346"
        }
      ],
      "source": "disclosure@vulncheck.com",
      "type": "Secondary"
    }
  ]
}

GHSA-WM9H-QWFM-WF3G

Vulnerability from github – Published: 2026-08-27 18:32 – Updated: 2026-08-27 18:32

Details

Severity

6.8 (Medium)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

7.6 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Show details on source website

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{
  "affected": [],
  "aliases": [
    "CVE-2026-81100"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-346"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-27T17:20:52Z",
    "severity": "HIGH"
  },
  "details": "tiger-gh-mcp-server started its MCP HTTP transport without enabling the host allow-list the underlying SDK provides. src/httpServer.ts called the shared httpServerFactory helper and never set the DNS-rebinding-protection option, so the transport accepted a request whatever host it named, making the locally reachable GitHub MCP endpoint drivable from a page in a visitor\u0027s browser that pointed a name it controlled at the bound address. The fix passes the option explicitly alongside a dependency update; the update alone would not have closed it. The repository has published no release that brackets the fix, so the affected boundary is the commit preceding it.",
  "id": "GHSA-wm9h-qwfm-wf3g",
  "modified": "2026-08-27T18:32:26Z",
  "published": "2026-08-27T18:32:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-81100"
    },
    {
      "type": "WEB",
      "url": "https://github.com/timescale/tiger-gh-mcp-server/pull/36"
    },
    {
      "type": "WEB",
      "url": "https://github.com/timescale/tiger-gh-mcp-server"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/timescale-tiger-gh-mcp-server-dns-rebinding-via-disabled-host-header-allow-list"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-81100 (GCVE-0-2026-81100)

FKIE_CVE-2026-81100

GHSA-WM9H-QWFM-WF3G

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